- It records all the proton-proton NOE’S occurring in a molecule in a single spectrum.
- it appears like 1H – 1H COSY spectrum. where as orthogonal axis is of the proton chemical shiftand the normal spectrum appears on the diagonal.
- NOESY is a space phenomena rather than bond interaction.
- NOESY spectrum provides information about geometry of molecule.
For Small molecule positive NOE – enhancements are rather weak and are often examined by NOE difference spectroscopy.
For large molecules, they can give more intense NOE cross-peaks and give a wealth of information regarding their geometry.
NOE is due to the mutual dipolar relaxation of the proton.
Here ,
Large cross peaks (r) = 2.0 – 2.5 A’
Medium cross peaks ( r) = 2.0 – 2.5 A’
Small Cross peaks (r) = 2.0 – 5.0 A’